1. Field of the Invention
The present invention relates to a device such as an indicator, switch or actuator for detecting the presence of a chemical contaminant. Such a detector is used, for example, in filling stations and chemical plants to detect the presence of unwanted chemicals.
2. Description of the Related Art
Chemical detection devices are frequently electronic and therefore have to be designed to be intrinsically safe making them prohibitively expensive for many applications and are dependent on the reliability of the power supply. Further, recent surveys in filling stations have shown that many of these devices have been physically disabled or no longer function for other reasons.